Bag-type packages have found widespread use for packaging of particulate and granular material, such as pet food, fertilizer, granular absorbents, and other diverse products. One typical instruction includes longitudinally extending gussets formed at opposite sides of the bag. A so-called square bottom seal, comprising a V-shaped seal which joins each of a front and rear wall of the bag body to a respective layer of each of the gussets, permits the bag to assume a generally rectangular configuration (with one end open) by permitting each of the gussets to open and unfold substantially along the length of the bag.
While the square bottom seal provided at the lower extent of the above-described bag generally forms and shapes the bottom of the bag to a rectangular configuration, the outer walls of the bag body will typically bulge outwardly to a round configuration under the influence of the pressure of product within the bag. This typical bulging can inhibit efficient handling and storage of filled packages, since each package tends to assume a generally outwardly bulged configuration.
Heretofore, efforts have been made to limit such outward bulging of package assemblies by providing an internal reinforcement layer which defines an effective circumference which is less than an effective circumference defined by an outer layer of the package assembly. U.S. Pat. No. 4,834,255, No. 4,927,037, and No. 5,071,025, all hereby incorporated by reference, illustrate various packaging constructions including inner and outer layers which respectively define differing peripheral dimensions.
The present invention is directed to a method and apparatus for highly efficient manufacture of a flexible bag assembly, including inner and outer layers, wherein the inner layer defines a circumference which is less than a circumference defined by the outer layer. As a consequence, a flexible package is formed which tends to assume and maintain a generally rectangular configuration, thus facilitating palletizing, and shipment and storage of particulate, granular, or other flowable materials for which the bag assembly is suited for use.